Indigenous bacteria and other microorganisms (e.g., yeasts) present in an oral cavity or on other biological surfaces adhere to various substrates (e.g., microorganisms of the same or different genus, teeth surface, epithelial surface) via receptor-modulated recognition mechanisms. Microorganisms in general express structures, generally termed "adhesins" which recognize and bind selectively to specific moieties called "receptors" found on microorganisms' surface or biological surfaces (e.g., teeth, oral cavity, skin, hair, or nails.) For example, some microorganisms express proteinaceous structures called "lectins" which recognize specific carbohydrate moieties; other microorganisms recognize specific peptide fragments of proteins (e.g., fibronectin) which typically form part of an epithelial surface. The adhesin/receptor modulated recognition mechanisms allow microorganisms to adhere with a high degree of selectivity and specificity to other microorganisms (of the same or different genus and/or species) and/or to a biological surface.
Recognition mechanisms of many microorganisms present in an oral cavity and on other biological surfaces have been identified. Fucose specific lectins have been described for several oral bacterial species, including those belonging to the genera Actinomyces, Capnocytophaga, and Streptococcus. Rhamnose specific lectins have been isolated from oral species including Capnocytophaga species. By far, the lectins most commonly expressed by plaque bacteria are .beta.-galactoside specific or "lacto sensitive" adhesins. The genera of the oral bacteria which produce .beta.-galactoside specific adhesins cover a diverse taxonomic range including Actinomyces, Streptococcus, Porphyromonas, Fusobacterium, Haemophilus, Capnocytophaga, Veillonella, Prevotella, Staphilococcus and Neisseria; these represent both primary and secondary colonizers of the teeth.
Numerous skin microorganisms interact with epithelial substrates through receptor-modulated recognition between cells' surfaces. Various skin microorganisms adhere preferentially to specific sites on various body surfaces. For example, Staphylococcus aureus, Streptococcus pyogenes and Pseudomonas aeruginosa adhere to collected nasal epithelial cells. Corynebacterium minutissimum and C. xerosis bind to epidermal cells. Yeast species such as Candida albicans, C. stellatoidea, C. parapsilosis, C. tropicales, C. krusei and C. guilliermondii bind to corneocytes. Dermatophytes such as Trichophyton quinckeanum, T. interdigitale and T. rubrum bind to keratinocytes from the sole of the foot, palm, dorsum of the hand, forearm and knee. Although the recognition process is complex, some of the specific structures involved in adherence of skin microorganisms are known. Polymeric glucosamine (chitosan) can inhibit the adherence of C. albicans to corneocytes. Lipoteichoic acid is the adhesin which Streptococcus pyogenes uses to attach itself to oral mucosal cells and this acid is also involved in the attachment of various streptococcal species to human stratum corneum cells. Lipoteichoic acid also interacts with the host cell receptors, one of which is fibronectin. Fibronectin carries two separate binding sites, one for streptococci and one for staphylococcii. Glucose and mannose washes have been used to remove coryneform and streptococcal species from the skin. Common skin microbes such as coryneform species involved in malodor generation and opportunistic pathogenic streptococcal species carry structures that recognize carbohydrates as well as fibronectin. Epithelial cells have "adhesin" recognition structures which interact with fatty acid side chains of lipoteichoic acid.
The use of specific structures such as saccharides, oligosaccharides, polysaccharides and glycoproteins to inhibit bacterial adherence and reduce associated accumulation of microbial films is dislosed in a number of patents: U.S. Pat. No. 4,349,772 details the use of an oligosaccharide derived from S. sanguis to prevent oral plaque accumulation; U.S. Pat. No. 5,002,759 describes use of an oligosaccharide to prevent adherence of Streptococcus pyogenes to epithelial cells; U.S. Pat. Nos. 4,992,420 and 4,994,441 disclose the use of milk-derived glycoproteins, e.g., .kappa.-casein, to prevent plaque accumulation. Japanese patent application 03220130 discloses the use of .kappa.-casein in dentrifices.
U.S. Pat. Nos. 5,130,122 and 4,971,788 describe dental hygiene products containing oil-in-water emulsions. A paper by S. Goldberg and M. Rosenberg, "Bacterial Desorption by Commercial Mouthwash vs. Two-Phase Oil:Water Formulations" (Biofouling, 3, 193-198, 1991) discusses the use of emulsions to remove in vitro bacterial films.
None of the above-cited publications describes an oil-in-water emulsion wherein oil droplets carry amphipathic molecules with biospecific head groups.
Although highly specific, the adhesin/receptor recognition interactions are non-covalent and generally reversible. Coaggregation reactions between complementary pairs of microrganisms or between microorganisms and biological surfaces can be inhibited by the presence in solution of the various moieties which are recognized by lectins. Competition for binding sites prevents or minimizes coaggregation or adherence. However, interactions between receptors and lectins are generally of low affinity. In nature, simultaneous, polyvalent (multisite) interactions between numerous adhesin/receptor pairs are used to achieve secure adherence.
It is an object of the present invention to provide a structure with multiple binding sites for binding to a microrganism or to a biological surface.
It is another object of the invention to provide an oil-in-water emulsion containing oil droplets carrying amphipathic molecules wherein the hydrophilic part of the amphipathic molecule contains a moiety recognized by a microorganism and/or by a biological surface.
It is yet another object of the invention to provide a composition for an effective delivery of an amphipathic compound to a microorganism or to a biological surface.
It is still another object of the invention to provide a method of delivering an amphipathic agent to a microorganism or to a biological surface.
It is still another object of the invention to provide an oil-in-water emulsion wherein oil droplets in the emulsion contain an active lipohilic ingredient and wherein oil droplets carry a biospecific amphipathic compound.
It is yet another object of the invention to provide a method of delivering an active lipophilic ingredient to the microorganism and/or to a biological surface.
It is yet another object of the invention to provide a composition for topical application to mammalian skin, hair, or nails which composition contains an oil-in-water emulsion including a biospecific amphipathic compound.
It is yet another object of the invention to provide an oral non-hygiene composition containing an oil-in water emulsion which includes a biospecific amphipathic compound.
These and other objects of the invention will become more apparent from the detailed description and the examples that follow.